Goodman GMV95 Won't Light

We just installed a Goodman GMV95 Two Stage furnace. As soon as turned on the electricity the first the it fired up right away and ran solid for an hour. A few hours later I realized the furnace was no longer on. We watched the light and it appears to be flashing continuously (or once, depending on how you read the manual) We have checked the grounds, look good, replaced the thermostat, cleaned the flame sensor with an emery board, scraped out the brass orifices with a paperclip, turned power on and off countless times and cannot figure this out. Any suggestions? We're going to call the gas company as well to have them come back out and look at it.